Expansible boring machine



Aug. 2,1927.

A. GOSPER EXPANSIBLE BORING MACHINE Fed Dec 27. 1926 I 2 Sheets-Sheet 1 w NN w N Sm Nm I 1,637,745 ug- 2 1927' A. GOSPER EXPANSIBLE BORING MACHI NE Filed Deo. 27, 1926 2 Sheets-Sheet 2 I /wrf/vrae 45 v f6? 60s/off;

Patented Aug. 2, 1927.

Amos GosPER, F BRIGHTON Lnsiiivns,v new soUtrHQwArinsnusiinALrA.'

'EXPAivsiBLn nomine This invention relates to an improved machine for boring in work-pieces'of wood or other material circular holes having straight entrance ends and expanded or enlarged por? tions at their inner' ends. Holes 'ot this kind are used largely in the manufacture of doors, cabinets andy other articles of joinery, wherein the parts are connected together by eXpansible dowels or similar connecting devices arranged to be concealed from view."y ',The principal object of thel invention is to provide an expansible boring machine having cutters of imiprovedv construction, simple and improved means for detachably and. interchangeably securing the cutters position,y and improv'ed means for automatically opening orexpanding the cutters'dur ingV the'boringl operations to Jform theen`- larged inner ends of the'holes.

Reference is made tothe accompanying drawings wherein Figure 1 is a longitudinalsectional view of the improved expansible boring machine. Figure 2' is a front view of the torward end of the boring machine;

Figure 3 is aview of the rear end of the machine. y v i Y' i" 'Figure 4', 5, 6 and 7 are' detail viewsi'Ll liistrating the cutters andthe means for' de` tachably and interchangeably securing@ the cutters in position. I. y. Figure v8 is asectional viewiof the forward end of tlie machine showingthe cuttersv in opened position for boring the expanded'inner end of ahole. i "y A v Figure 9l is a detail view ofthe rotating spindle which carries tlie'cutters.

Figures 10 and 11 are detail views of the partl 27.l hereinafter described.

" forked control Figure 12' is a view of the member shown inI Figure 1. f

Figures 13, 14k and. 15 'are views illustratingthe't'ubular base; member ofthe machine and the brackets carried thereby.` The/improved' eXpansible boring machine comprises a base member 2 off tubular construction, which is'preerably formed in two interfitting sections andf is mountedupon a suitablemachine bed or iframe 3i The base member 2 may,.beislidablex on the'bed' toeiiable the machinet'o be 'conveniently adjustedto-d'ii'erent positions for boring holes in relatively largework-pieces which require tobe supported in vises or clamping appliances. n i i The basemember'is ordifnarily'disp'osed shapes andr sinesare provided `for 'inter'- Appiicanon ined December e?, iszegseriai ntfisvzasraa y,ifi nu.stifai'ia.May"5,'1926.

h'orizoi'ita'lly` and"rigic'lly supports a lcylindrical casing ,4 wlil'eifein a rotatable spindle 5 is' jurn'a'led in 4bearing bushes 6. These bearing bushes arek accommodated in holders 7, which are tted. in shallow recesses 8 formedlin the end vportions of the casing 4. A thrust bearing 9 is provided at the rear end'of'the casing 4L to rotatably support they end of the spindle 5, and packing washers 10 and'11 of'ibre orflike suitable I material arefitt'ed into opposite ends of the'casjng to pre-j vent escape of llubricant from' the lworkingparts of the machine. 3

Formed at the forward endfof the spindle 5 4is' afd'iametrical"slotwayy12 wherein two toolv holders ,'13 'are pivoted on a detachable .pin 141.l vThese toolv holders lare illustratedv in detailinFigures 4to 7 ,and each is constructed having ang' integral control armV 15 tol extend Ireafrwardly within the'sl'otway 12, and a'circular jsocket-"like member 16 which is" centralllyfape'rtured. at' 17`V to receive the pix-16a piniiul The cutters is or the machine are detachably and/interchangeably`itted into the tool'holders r13 andare arranged to 'abut in-sci'ssors-like fashion' as shown in Figure 5; Each cutter fhas a blade 19- formed withv a' straight cutting edge 20Nand with an inclined orangular'cutting l edge 21 disposed 'at the outer end ofthe said* straight cutting A circiila-rfplate22 having a hole 23 is yprovided at the inner end-'of each cutter and is adaptedifor "detachable tment into the socl et=16 of the tool'hol'der,v the hole 23 re'- rceivingthe pivotpin-lt. To prevent lateral Y movement of the cutters 18y when tted l'in 'position in their,4r tool holders, gapsv21vare formed-in-the'walls 25 of the tool holder `sockets`16 and are so arranged as to` snugly receivefth'e-steni onbl'ade portions of thecutters.` l l "A' plurality of cutters 18 Vof different changeable iitment into-the tool` holders for boring holes of different diameters or having eXpand'edinner ends-ot varying sizes. In changing the cutters, the pivot pin 14 is hrst withdrawn andthe two tool holders 18 together vwitlrthe l'cutters are removed from 'the slotway '12. TheV tool-sholders are vthen separated when` the existing cutters are iieirioved] from the sockets -16 'and' the required cut-ters are itted in position.

- Foi-'med axially :ini the spindleb Y isf-a hole 26`wherein a stem or rod v27 is slidablyiitted.

, commodated in the slotway 12 ofthe spindle Y and is formed-having two inclined internal surfaces 29 engaging the ends ofthecontrol arms 15 of the tool holders. When the stem 27 is, slidably moved within the axial hole 26, the inclined surfaces 29 on the flat block28 actuate the control arms 15 causing the cutters `to be moved apart inan opening movement to thusl form the 4expanded inner ends of the holes being bored. e a

To automatically return the cutters to normal positionafter a hole has been bored, a spring 30substantially of U-shape is fitted in a circular hole 31 inthe iiat block 28 and is arranged With its arms 32 bearing against the internal` surfaces of the cutter control arms 15,` constantly maintaining` said con trol arms `in engagement with the inclined surfaces 29 of the block 28. i Y l Fitted around the stem 27 is a coiled spring 33 havingits forward end anchored and the cutters `,"l8fto normal position after each boring .operation performed by the machine.v f i i Secured 1 to the` rear end of the machine f base 2"byscrews 36 `is a bracket 37 designed to partly encircle the end of the cylindrical casing 4. i The said bracket is formed hav` ingtwo oppositelydisposed pins or studs 38 `on which are centrally pivoted two levers 39 coupled together at` theiropposite ends by pins 40 and41 respectively. The pin4() isV i pivotally connected toone endl of `a rod 42' which is slidable-ina` guide boss 43 formed e on the basebracket 37. i This` rod 42 carries an arm 44 connected to aspindle 45 slidably mounted i in the guide bush 35 fitted in the rear end of the machine spindle 5. A thrust i ballv 46.is provided between the end of the lib spindle l45 and the rear end of the stem 27 so that movement of the former is-freely transmitted to fsaid stem to actuate the `cutters` 18 `of the machine `without interfering. `.with the rotary movement of the spindle 5 and said stem 27.

The` pin 41- at the opposite end of the levers 39 is pivotally connected to a rod 47, which is slidable in a guide sleeve 48 mounted inapertured members 49 secured to the upper section `ot' the machine base member `2. The vforward end of the rod 47 is fitted with` a forked control member 50, which has two arms 51 arranged one on each side of the cutters 18` as is` shown clearly in Figure2. u

The machine is adapted to be driven at high speed by a belt 52 Whichpaeses around a pulley wheel 53 keyed onto the rear end of the machine spindle 5. Iii' desired,a gear wheel 54 may be fittedon the machine spinldle adjacent" tothe pulley wheel 53 and by gearingthe same to an adjacent machine or machines a-gang of machines can vbe simultaneously driven by a. single power belt. Y

In the operation of the machine, `the Workpiece'or workpieccs 55 to be bored' are first forced inwardly against the 4rotating l `cutters 18. These cutters wlieniirst con-A tacting withthe workpieces arein closed position `as shoWn'in Figure l, andtliey thus` borethe straight entrance endi'o'l' the hole. When a predetermined depth oit hole hasV been bored, the workpiece contacts witli` the forked control member 50-and moves it in-` wardly thus actuating. the levers 39 through the slidingfrod 47 Aand the pin 41. flhe le-` vers39, in turn, slidably move the rod 42; and cause the spindle 45 to `be slidably moved Within its guide bush`35, .thus ,actu-5 ating the stem 27 through the thrust ball 46 and causing the cutters 18to "begopened in the manner previouslyV describediThe opening movement of the cutters takes;y place gradually as the` Workpiece sloyvlyiacftuates the forked control memberHand:` afresult the `enlarged inner portion `of thel hole is boreduniformly. c e; a i l/Vhen the Work-piece is reniovecliironi the machine, the coiled springf33 automatically returns the stem 27, the forked controlinember 50 and other slidable parts of themachine .to initial position,while the U-spring 30 causesthe cutters ,lwto be moved Vto closed position., Y 4 v What-I do claimis`:` 1 i `1. An improved boring machineor boring holes having enlargedyinner ends comprising, a casing, a spindle rotatable in said cas1ng,`a pair of tool holders .pivotally carried by said spindle, control arms` on-said tool holders extendingninwardly into. the casing, cutters carried by said ltoolholders,

a stem slidable withinthe spindle and adapted to engage said control arms, and acontrol member mounted: adjacent.` to `thecut- .ters and adapted to be actuated by the workrpieces being bored to slidabl move, the .stem

member and thus automat1cally7open the cutters to `formthe enlarged inner ends of e the holes being bored. l e ,e

2. An improvedieboring machine for boring holes having enlarged Sinner. ends comprising, a casing, a spindle mounted inbearings in said casing,mea ns for rotating said spindle, a pair of tool holders pivotally carried at one end of said spindle,control arms on said tool `holders extending inwardly into the casing, cutters interchangeably carried by said tool holders, a stem slidable within A the spindle and adaptedtto `engage said control arms'cto open the `cutters. to form the enlarged inner ends of the holes being bored, a forked control member arranged around the cutters and adapted to be engaged by the work-piece being bored, and connections between said forked control member and the slidable stem whereby the cont-rol arms of the tool holders are actuated to open the cutters when the forked control member is moved inwardly by the workpiece.

3. An improved boring machine as claimed in claim 2, and wherein the spindle is formed with a slotway to receive a block fit-ted on the end of the slidable stem,l and internal inclined faces are provided on said block to engage the control arms of the tool holders.

4. An improved boring machine as claimed in claim 2, and wherein the tool holders are mounted on a pivot pin at the end of the rotatable spindle and are formed ywith socket-s which detachably receive circular plates formed at the inner ends of the cutters.` f

' 5. An improved boring machine as claim ed in claim 2, and wherein a coiled spring surrounds the slidable stem to automatically return said stem and the forked control member to initial position when the workpiece is removed from the machine, and wherein a spring is fitted between the control arms of the tool holders to close the cutters after boring operations.

6. An improved boring machine for boring yholes having enlarged inner ends comprising, a base member, a casing carried by said base member, a spindle mounted 1nbearings in'said casing, means for rotating f slidable in the slotway of the spindle, in-

ternal inclined surfaces on said block engaging the control arms of the tool holders to automatically open the cutters when said stem is actuated, a spring carried by said flat block and engaging said control arms to close the cutters after boring operations, brackets secured to the machine base member, levers carried by said b-rackets, a forked control member fitting around the cutters and adapt-ed to be actuated by the workpiece being bored, connections between the forked member and said levers, and further connections between said levers and the slidable stem whereby said stem is slidably moved Within the spindle to open the cutters when the forked control member is actuated.l

In testimony whereofl aiiiX` my signature.

AMOS GOSPER. 

